WO2006113045A1

WO2006113045A1 - Customized processing in association with finite element analysis

Info

Publication number: WO2006113045A1
Application number: PCT/US2006/010808
Authority: WO
Inventors: Allen W. Chi
Original assignee: The Boeing Company
Priority date: 2005-04-18
Filing date: 2006-03-24
Publication date: 2006-10-26
Also published as: US20060235660A1; JP5124445B2; EP1872287A1; JP2008537261A; EP1872287B1

Abstract

A facility provides functionality for performing customized analysis on finite element models. The facility may include a finite element post processing framework, wherein the finite element post processing framework is not specific to a particular finite element model. The facility may also include an interface component configured to receive input from an end user, wherein the interface component receives input associated with customizing the post processing framework so that it can be applied to a specific finite element model. The facility may then perform processing, such as post processing, on the specific finite element model based on customizing the post processing framework.

Description

CUSTOMIZED PROCESSING IN ASSOCIATION WITH FINITE

ELEMENT ANALYSIS

BACKGROUND

[0001] Finite-element models are an important tool in the design and verification of many engineered structures and systems. For example, finite element models may define a working environment in terms of forces, accelerations, etc., and can thus be used to determine structural integrity of an engineered structure within that working environment. Through the use of finite element models, it is possible to break a complex system down into a manageable (finite) number of elements (e.g., a curve drawn as a series of steps). Finite element models may be used for several purposes.

For example, finite element models may help determine the behavior of a new airplane product design under various load environments.

[0002] Because of the interdisciplinary nature of finite element models (which typically combine concepts from mathematics, physics, engineering and computer science), generating and using a finite element model typically involves multiple phases such as a pre-processing phase, a processing phase, and a post processing phase. During the pre-processing phase, a finite element analyst uses one or more computer programs to develop a finite element model. In the case of a structure, this may include creating a finite element mesh to divide the structure's geometry into subdomains for mathematical analysis and applying material properties and boundary conditions to this geometry. During the processing phase, a finite element analysis program derives and solves governing matrix equations from the model created during pre-processing. During the post processing phase, the analyst uses one or more programs to check the validity of the solutions from the processing phase (e.g., displacements, stresses, specialized stresses, error indicators, etc.) and to perform other analysis.

[0003] Most customized post processing programs are model-specific, meaning they are hard coded to fit a designated finite element model representing a known structure. Thus, a new programming effort may be need for new finite element models, and any changes to an existing model's geometry, design configuration, interface modeling, and output requirements may lead to additional programming efforts. Once configured, many of these post processing programs are in a rigid format and are difficult to expand or change. As a result, numerous sets of post processing programs may be required when multiple structures or structure variations are being modeled. For example, each time a new finite model is to be analyzed, a programmer may need to write and compile a new post processing program (e.g., in a programming language such as FORTRAN, Java, C++, etc.) for that specific finite element model.

SUMMARY

[0004] A computerized facility providing a flexible scheme for analysis of finite element models is disclosed. In some embodiments, the facility allows the user to create a set of control files to define a customized processing routine that can be applied to a specific finite element model, without having to write or rewrite any programming code. For example, a non-programmer can use an interface provided by the facility to configure various aspects of a post processing routine (instead of having to write and compile a new program using a programming language such as Fortran, Java, C, C++, C#, J#, etc.). Via this interface, the user may provide model-specific attribute information that can then be applied to a flexible post processing scheme to produce a customized post processing result. The facility may be implemented using object-oriented concepts and/or other programming concepts.

[0005] In some embodiments, the facility may include a finite element post processing framework, wherein the finite element post processing framework is not specific to a particular finite element model. Customizing the post processing framework may include configuring a control file to control one or more processes associated with the post processing framework. The finite element post processing framework may be based, at least in part on one or more data structures, including, for example, a database element, an interface element including a collection of degrees of freedom connecting two or more structural components, a freebody element for collecting interfaces and assembling load balance tables of components, a summary element for processing and sorting a selection of interfaces and generating a summary table, a utility functions element, a post element instantiated according to an overall process flow and scope of post processing, a graphical user interface element, etc. [0006] The facility may also include an interface component configured to receive input from an end user, wherein the interface component receives input associated with customizing the post processing framework so that it can be applied to a specific finite element model. In some embodiments, the end user does not perform hard coding when providing input to the interface. The input from the end user may include interface information specific to the finite element model, local coordinate information specific to the finite element model, component information specific to the finite element model, summary table preferences for use in generating a summary table resulting from the post processing, etc. [0007] In some embodiments, processing and/or post processing is performed on a specific finite element model by a method comprising receiving input for use in generating one or more control instructions (e.g., control files) to define a customized processing routine that can be applied to a specific finite element model, wherein receiving the input does not include a user writing or rewriting programming code, and generating the one or more control instructions based on the received input, including applying the received input to a generic processing framework, wherein generating the control instructions does not include a user writing or rewriting programming code.

BRIEF DESCRIPTION OF THE DRAWINGS

[0008] Figure 1 is a block diagram showing an example of a representative environment in which the finite element model post processing scheme may be implemented.

[0009] Figure 2 is a block diagram showing an object-oriented implementation of the finite element model post processing scheme.

[0010] Figure 3 is a data diagram showing various sample data structures associated with an example implementation of the finite element post processing scheme.

[0011] Figure 4 is a data diagram showing various classes associated with an example implementation of the finite element post processing scheme.

[0012] Figure 5 is a flow diagram showing an overview of a routine for configuring a post processing control file. [0013] Figure 6 is a flow diagram showing a routine for defining an interface for configuration of a post processing control file.

[0014] Figure 7 is a flow diagram showing a routine for defining a focal coordination system for configuration of a post processing control file. [0015] Figure 8 is a flow diagram showing a routine for defining a component for configuration of a post processing control file.

[0016] Figure 9 is a flow diagram showing a routine for defining a summary table for configuration of a post processing control file.

DETAILED DESCRIPTION

1. Representative Environment

[0017] Figure 1 and the following discussion provide a brief, general description of a suitable computing environment in which the post processing facility can be implemented. Although not required, embodiments of the post processing facility will be described in the general context of computer-executable instructions, such as routines executed by a general purpose computer, e.g., a server or personal computer. Those skilled in the relevant art will appreciate that the post processing facility can be practiced with other computer system configurations, including Internet appliances, hand-held devices, wearable computers, cellular or mobile phones, multi-processor systems, microprocessor-based or programmable consumer electronics, set-top boxes, network PCs, mini-computers, mainframe computers and the like. The post processing facility can be embodied in a special purpose computer or data processor that is specifically programmed, configured or constructed to perform one or more of the computer-executable instructions explained in detail below. The post processing facility can also be practiced in distributed computing environments where tasks or modules are performed by remote processing devices, which are linked through a communications network. In a distributed computing environment, program modules may be located in both local and remote memory storage devices. Indeed, the term "computer", as used generally herein, refers to any of the above devices and systems, as well as any data processor. [0018] Aspects of the post processing facility described below may be stored or distributed on computer-readable media, including magnetic and optically readable and removable computer disks, as well as distributed electronically over the Internet or over other networks (including wireless networks). Those skilled in the relevant art will recognize that portions of the post processing facility reside on a server computer, while corresponding portions reside on a client computer. Data structures and transmission of data particular to aspects of the post processing facility are also encompassed within the scope of the post processing facility.

[0019] Referring to Figure 1 , a conventional personal computer 100 includes a processing unit 102, a system memory 104, and a system bus 106 that couples various system components including the system memory to the processing unit 102. The processing unit 102 may be any logic processing unit, such as one or more central processing units (CPUs), digital signal processors (DSPs), application-specific integrated circuits (ASIC), etc. Unless described otherwise, the construction and operation of the various blocks shown in Figure 1 may be of conventional design. As a result, such blocks need not be described in further detail herein, as they will be readily understood by those skilled in the relevant art.

[0020] The system bus 106 can employ any known bus structures or architectures, including a memory bus with memory controller, a peripheral bus, and a local bus. The system memory 104 may include read-only memory ("ROM") 108 and random access memory ("RAM") 110. A basic input/output system ("BIOS") 112, which can form part of the ROM 108, contains basic routines that help transfer information between elements within the personal computer 100, such as during start-up.

[0021] The personal computer 100 also includes a hard disk drive 114 for reading from and writing to a hard disk (not shown), and an optical disk drive 116 and a magnetic disk drive 118 for reading from and writing to removable optical disks 120 and magnetic disks 122, respectively. The optical disk 120 can be a CD-ROM, while the magnetic disk 122 can be a magnetic floppy disk. The hard disk drive 114, optical disk drive 116, and magnetic disk drive 118 may communicate with the processing unit 102 via the bus 106. The hard disk drive 114, optical disk drive 116, and magnetic disk drive 118 may include interfaces or controllers (not shown) coupled between such drives and the bus 106, as is known by those skilled in the art. The drives 114, 116, and 118, and their associated computer-readable media, provide nonvolatile storage of computer readable instructions, data structures, program modules, and other data for the personal computer 100. Although the depicted personal computer 100 may employ a hard disk, optical disk 120, and magnetic disk 122, those skilled in the relevant art will appreciate that other types of computer-readable media that can store data accessible by a computer may be employed, such as magnetic cassettes, flash memory cards, digital video disks ("DVD"), Bernoulli cartridges, RAMs, ROMs, smart cards, etc.

[0022] Program modules can be stored in the system memory 104, such as an operating system 124, one or more application programs 126, other programs or modules 128, and program data 130. The application programs 126 include finite element analysis facilities or applications 129, including a post processing facility 131. While shown in Figure 1 as being stored in the system memory 104, the operating system 124, application programs 126, other modules 128, and program data 130 can be stored on the hard disk of the hard disk drive 114, the optical disk 120 of the optical disk drive 116, and/or the magnetic disk 122 of the magnetic disk drive 118. A database 133 that stores information for finite element models and analysis may also be present (either external or internal to the personal computer 100).

[0023] A user can enter commands and information into the personal computer 100 through input devices such as a keyboard 132 and a pointing device such as a mouse 134. Other input devices (not shown) can include a microphone, joystick, game pad, scanner, etc. These and other input devices are connected to the processing unit 102 through an interface 136 (e.g., a serial port interface, a parallel port, game port, universal serial bus ("USB") etc.) that couples to the bus 106. A monitor 138 or other display device may be coupled to the bus 106 via a video interface 140, such as a video adapter. The personal computer 100 can include other output devices, such as speakers, printers, etc.

[0024] The personal computer 100 can operate in a networked environment using logical connections to one or more remote computers, such as a remote computer 150. The remote computer 150 can be another personal computer, a server, a router, a database, a network PC, a peer device or other common network node, and typically includes many or all of the elements described above for the personal computer 100. Typically, the remote computer 150 includes a memory storage device such as a disk drive 152 shown in Figure 1. The remote computer 150 is logically connected to the personal computer 100 under any known method of permitting computers to communicate, such as through a local area network ("LAN") 154 or a wide area network ("WAN") or Internet 156. Such networking environments are well known in offices, enterprise-wide computer networks, intranets and the Internet.

[0025] In a LAN networking environment, the personal computer 100 is connected to the LAN 154 through an adapter or network interface 158 (coupled to the bus 106). When used in a WAN networking environment, the personal computer 100 often includes a modem 160 or other device for establishing communications over the WAN/Internet 156. The modem 160 is shown in Figure 1 as coupled between the interface 136 and the WAN/Internet 156. In a networked environment, program modules, application programs, or data, or portions thereof, can be stored in the remote computer 150, such as in the disk drive 152. Those skilled in the relevant art will readily recognize that the network connections shown in Figure 1 are only some examples of establishing communication links between computers, and other links may be used, including wireless links. In general, while hardware platforms, such as the personal computer 100 and remote computer 150, are described herein, aspects of the post processing facility are equally applicable to nodes on a network having corresponding resource locators to identify such nodes. [0026] Figure 2 is a block diagram showing an example of actions performed by a post processing facility 200. In some embodiments, a post processing process management module 202 performs various tasks associated with post processing of a finite element model. To allow for customization, the post processing process management module 202 may be controlled, at least in part, by a post processing control component 204. The post processing control component may be based, at least in part, on information provided by an end user via an end user interface 203, which is then configured using a control component configuration engine 205. [0027] Tasks performed by the post processing process management module 202 (under the at least partial control of the control component 204) may include a define configuration task 206, a process interface loads task 208, a process load balances task 210, and a process summary tables task 212. As illustrated, many of the tasks associated with the process management module 202 may be performed, for example, in the context of object oriented programming. For example, attribute information provided by the post processing control component 204 may be introduced into an object oriented environment to instantiate various objects used in performing the tasks (206, 208, 210, and 212).

[0028] An example of an engine freebody output resulting from performing post processing on a finite element model relating to aircraft design is shown in the following table:

Table A 2. Data structure

[0029] Figure 3 is a data diagram showing various data structures used in collecting information from an end user (e.g., an end user who is familiar with finite element models, but who need not exercise programming skills). In turn, this information may be used to configure a post processing control file. In some embodiments, the various data structures may include an interface data structure 310, a local coordination system data structure 320, a component data structure 330, and a summary table data structure 340, although other data structures or combinations of data structures are possible in the context of receiving input from an end user.

[0030] The interface data structure 310 may include various types of interface- related information specific to a particular finite element model that is to be the subject of post processing. In some embodiments, this information may include nodal coordinate information 310, element ID information 312, coordinate system information 314, sign convention information 316, and linear combination information 318. In some cases, this information is provided by an end user. An example of the contents of the interface data structure 310 is illustrated in the following table:

Table B

[0031] The local coordinate system data structure 320 may contain information for one or more coordinate systems used in defining the finite element model that is the subject of the post processing. As with the interface data structure 310, the information associated with the local coordinate system data structure 320 may be provided by an end user. An example of the contents of the local coordinate system data structure 320 is illustrated in the following table:

Table C

[0032] The component data structure 330 may include information on various components within the finite element model subject to the post processing, as provided, for example, by an end user. For example, the component data structure 330 may include label information 332, reference point information 334, boundary information 336, and output requirements 338 for one or more components. An example of the contents of the component data structure 330 is illustrated in the following table:

Table D [0033] The summary table data structure 340 may, likewise, include heading information 342, footnote information 344, and degrees of freedom (DOF) information 346, as provided, for example, by an end user. An example of the contents of the component data structure 330 is illustrated in the following table:

Table E

[0034] This collection information described above, as well as other information, may be combined to configure a post processing control file to be used in a post processing program or other post processing routine specific to the finite element model under analysis. In this way, custom information can be provided to a generic post processing scheme, such as an object oriented post processing scheme to allow a non- programming end user to customize a post processing program to fit a specific finite element model in a way that is easy to use and does not require any hard coding by an end user. [0035] Figure 4 is a data diagram showing various classes associated with an implementation of the post processing scheme, such as an object oriented implementation. A database class 402 may be used to process and store data generated from integrated finite element analysis. An example of an object instantiated from such a class includes a design load analysis object. An interface class 404 may be associated with a collection of degree of freedoms (DOFs) connecting two structural components. Two subclasses that may inherit from the interface class 404 may include a rectangular subclass and a cylindrical subclass. These subclasses are defined individually to process two different types of interfaces. For example, a rectangular subclass interface may process interfaces defined in a rectangular coordinate system (e.g., a pylon to a wing attachment). A cylindrical subclass may be configured to process interfaces defined in cylindrical coordinate systems (e.g., any ring interfaces such as an inlet to an engine attachment).

[0036] A freebody class 406 may be used to collect multiple interfaces and assemble load balance tables of components defined within such interfaces. In addition, the freebody class 406 may include functionality to perform freebody balance checks of such components. Examples of the components include an engine, a strut, and a wing. A summary class 408 may be associated with functionality to process and sort a selection of interfaces and generate a summary table (e.g., a summary table associated with a load release document). For example, the summary class 408 functionality may be used to analyze an engine mount load summary and a wing attachment load summary.

[0037] In some embodiments, a utility function class 410 may be used to collect a group of utility functions associated with post processing. Based on the collected utility functions, a post object 412 may be instantiated according to the user input control file to control the overall process flow and scope of post processing. In addition, a graphical user interface object 414 may be instantiated to provide the end user with information associated with such post processing.

[0038] Figure 5 is a flow diagram showing a routine 500 for generating and/or configuring a post processing control file. At block 501 the routine 500 may define one or more interfaces based, for example, on end user input. At block 502 the routine 500 may define one or more coordinate systems based, for example, on end user input. At block 503 the routine 500 may define one or more components based, for example, on end user input. At block 504 the routine 500 may define one or more summary tables based, for example, on end user input. At block 505 the routine 500 may configure one or more system control files based on the information received with respect to blocks 501 , 502, 503, and 504, as well as possibly other information. The routine 500 then ends. [0039] Figure 6 is a flow diagram showing an example of a routine 600 for defining an interface (e.g., such as with respect to block 501 of Figure 5). At block 601 the routine 600 may define one or more nodal coordinate systems for the post processing based, for example, on end user input. At block 602 the routine 600 may define one or more element IDs associated with each element of the finite element model subject to post processing based, for example, on end user input. At block 603 the routine 600 may define one or more coordinate systems associated with the finite element model subject to post processing based, for example, on end user input. At block 604 the routine 600 may define sign conventions for the finite element model associated with the post processing based, for example, on end user input. At optional block 605 the routine 600 implements optional linear combination definitions based, for example, on end user input. The routine 600 then ends.

[0040] Figure 7 shows an example of a routine 700 for defining a coordinate system in conjunction with creating a control file for post processing. At block 701 the routine 700 may define a new local coordinate system based, for example, on end user input. At decision block 702 the routine 700 may check for additional coordinate system. If none are found the routine 700 ends. Otherwise the routine 700 loops back to block 701 to define a next local coordinate system.

[0041] Figure 8 shows an example of a routine 800 for defining components in association with creating a control file for post processing a finite element model. At block 801 the routine 800 may define label information based, for example, on end user input. At block 802 the routine 800 may define reference point information based, for example, on end user input. At block 803 the routine 800 may define boundary information based, for example, on end user input. At block 804 the routine 800 may define output requirements based, for example, on end user input. The routine 800 then ends.

[0042] Figure 9 shows an example of a routine 900 for defining a summary table in accordance with configuring a control file for controlling a post processing routine. At block 901 the routine 900 may define heading and footnote information based, for example, on end user input. At block 902 the routine 900 may select an interface based, for example, on end user input. At block 903 the routine 900 may select node information and degrees of freedom information based, for example, on end user input. The routine 900 then ends.

[0043] From the foregoing, it will be appreciated that specific embodiments of the invention have been described herein for purposes of illustration, but that various modifications may be made without deviating from the invention and aspects of the invention described in the context of particular embodiments may be combined or eliminated in other embodiments. Although advantages associated with certain embodiments of the invention have been described in the context of those embodiments, other embodiments may also exhibit such advantages. Additionally, none of the foregoing embodiments need necessarily exhibit such advantages to fall within the scope of the invention.

Claims

CLAIMSI/We claim:

1. A system for performing analysis on finite element models, the system comprising: a finite element post processing framework, wherein the finite element post processing framework is not specific to a particular finite element model; a user interface component configured to receive input from an end user, wherein the user interface component receives input associated with customizing the post processing framework so that it can be applied to a specific finite element model; and a post processing component configured to perform post processing on the specific finite element model based on customizing the post processing framework.

2. The system of claim 1 wherein customizing the post processing framework includes configuring a control file to control one or more processes associated with the post processing framework.

3. The system of claim 1 wherein the post processing framework is implemented using object oriented programming.

4. The system of claim 1 wherein the input from the end user includes: interface information specific to the finite element model; local coordinate information specific to the finite element model; component information specific to the finite element model; and summary table preferences for use in generating a summary table resulting from the post processing.

5. The system of claim 1 wherein the input from end users includes: interface information specific to the finite element model, wherein the interface information includes nodal coordinate information, element identifier information, sign convention information, and linear combination information; local coordinate information specific to the finite element model; component information specific to the finite element model, wherein the component information includes label information, reference point information, and boundary information; and summary table preferences for use in generating a summary table resulting from the post processing, wherein the summary table information includes heading information, footnote information, and degrees of freedom information.

6. The system of claim 1 wherein the finite element post processing framework is based, at least in part on one or more data structures comprising: a database element; an interface element including a collection of degree of freedoms each connecting two structural components; a freebody element for collecting boundary interfaces and assembling load balance tables of components; a summary element for processing and sorting a selection of interfaces and generating a summary table; a utility functions element; a post element instantiated according to an overall process flow and scope of post processing; and a graphical user interface element.

7. The system of claim 1 wherein the end user does not perform hard coding when providing input to the interface.

8. The system of claim 1 wherein the input from the end user includes: interface information specific to the finite element model, local coordinate information specific to the finite element model, component information specific to the finite element model, and summary table preferences for use in generating a summary table resulting from the post processing; and wherein the finite element post processing framework is based, at least in part on one or more data structures comprising: a database element, an interface element including a collection of degree of freedoms each connecting two structural components, a freebody element for collecting boundary interfaces and assembling load balance tables of components, a summary element for processing and sorting a selection of interfaces and generating a summary table, a utility functions element, a post element instantiated according to an overall process flow and scope of post processing, and a graphical user interface element.

9. A computer-readable medium containing instructions for performing a method for configuring a post processing program for use on a finite element model, the method comprising: receiving interface information for the post processing program, wherein the interface information is specific to a finite element model; receiving model-specific local coordinate information for the post processing program, wherein the local coordinate information is specific to the finite element model; receiving component information for the post processing program, wherein the component information is specific to the finite element model; receiving summary table preferences for the post processing program; and configuring a system control file based on the received interface information, the received local coordinate information, the received component information, and the received summary table preferences, wherein the system control file controls and provides attribute information to a post processing software facility.

10. The computer-readable medium of claim 9 wherein the post processing software facility is an object oriented post processing software facility.

11. The computer-readable medium of claim 9 wherein the post processing software facility is defined, at least in part, based on one or more software programming classes including at least one of: a database class, an interface class including a collection of degree of freedoms each connecting two structural components, a freebody class for collecting boundary interfaces and assembling load balance tables of components defined based on the input from the end user, a summary class for processing and sorting a selection of interfaces and generating a summary table, a utility functions class, a post class instantiated according to an overall process flow and scope of post processing, and a graphical user interface class.

12. The computer-readable medium of claim 9 wherein the post processing software facility is defined, at least in part, based on one or more software programming classes including an interface class including a collection of degree of freedoms connecting two or more structural components, wherein the interface class is associated with a rectangular coordinates subclass and a cylindrical coordinates subclass.

13. The computer-readable medium of claim 9 wherein the received interface information, the received local coordinate information, the received component information, and the received summary table preferences, are provided by an end user without programming knowledge.

14. The computer-readable medium of claim 9 wherein the computer-readable medium includes a logical node in a computer network receiving the contents.

15. The computer-readable medium of claim 9 wherein the computer-readable medium is a computer-readable disk or tape.

16. The computer-readable medium of claim 9 wherein the computer-readable medium includes a data transmission medium carrying a generated data signal containing the contents.

17. The computer-readable medium of claim 9 wherein the interface information includes one or more of nodal coordinate information, element identifier information, coordinate system information, sign convention information, and linear combination information associated with a particular finite element model.

18. A method for conducting processing of a finite element model, the method comprising: receiving input for use in generating one or more control files to define a customized processing routine that can be applied to a specific finite element model, wherein receiving the input does not include a user writing or rewriting programming code in a programming language; and generating the one or more control instructions based on the received input, including applying the received input to a generic processing framework, wherein generating the control instructions does not include a user writing or rewriting programming code.

19. The method of claim 18, further comprising performing post processing on one or more finite element models based on the one or more control instructions.

20. The method of claim 18, further comprising performing post processing on one or more finite element models based on the one or more control instructions, wherein in post processing includes: defining a configuration for the post processing based, at least in part, on the one or more control instructions; processing interface loads based, at least in part, on the one or more control instructions; processing load balances based, at least in part, on the one or more control instructions; and processing summary tables based, at least in part, on the one or more control instructions.

21. The method of claim 18 wherein the received input is collected in one or more data structures stored on a computer-readable medium, wherein each of the one or more data structures includes one or more type of information from a group comprising: interface information specific to the finite element model; local coordinate information specific to the finite element model; component information specific to the finite element model; and summary table preferences specific to the finite element model.

22. The method of claim 18 wherein the generic processing framework is an object oriented post processing framework.

23. The method of claim 18 wherein the processing framework is associated with a post processing aspect of a finite element analysis application.

24. The method of claim 18 wherein the input is received via an end user interface and includes data but not explicit relationships between data.

25. The method of claim 18 wherein generating the control instructions is performed, at least in part, by a control component engine.